From now on, none of the LBM usual materials are able to withstand the high mechanical loads in aerospace bearings or gears. To achieve these high mechanical performances, 33CrMoV12, a common forged carbon aerospace steel with a nitriding treatment, has been argon-atomized for the first time and used in a DMLS machine. In this study, the initial microstructure is characterized to show a cellular pattern. This dual-phase microstructure has been characterized by nano-SIMS analysis to evidence micro-segregation. Several heat treatments are then tested to reach mechanical properties of the forged material: tempered, quenched / tempered, double-tempered and normalized / quenched / tempered. Each one is characterized by means of tensile tests, impact toughness and phase analysis. Very encouraging results have been obtained, paving the way for original heat treatments.